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implement /dev/kmsg loggin

This commit is contained in:
Lennart Poettering 2010-01-27 23:32:50 +01:00
parent b52429d4e0
commit 4901f97278
1 changed files with 95 additions and 32 deletions
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99
logger.c
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@ -11,6 +11,7 @@
#include <sys/poll.h>
#include <sys/epoll.h>
#include <sys/un.h>
#include <fcntl.h>
#include "util.h"
#include "log.h"
@ -25,7 +26,8 @@
typedef struct Stream Stream;
typedef struct Server {
int log_fd;
int syslog_fd;
int kmsg_fd;
int epoll_fd;
unsigned n_server_fd;
@ -35,25 +37,33 @@ typedef struct Server {
} Server;
typedef enum StreamState {
STREAM_LOG_TARGET,
STREAM_PRIORITY,
STREAM_PROCESS,
STREAM_RUNNING
} StreamState;
typedef enum LogTarget {
LOG_TARGET_SYSLOG,
LOG_TARGET_KMSG
} LogTarget;
struct Stream {
Server *server;
StreamState state;
int fd;
LogTarget target;
int priority;
char *process;
pid_t pid;
uid_t uid;
char buffer[STREAM_BUFFER];
size_t length;
pid_t pid;
LIST_FIELDS(Stream, stream);
};
@ -66,8 +76,6 @@ struct Stream {
static int stream_log(Stream *s, char *p, usec_t timestamp) {
char header_priority[16], header_time[64], header_pid[16];
time_t t;
struct tm *tm;
struct msghdr msghdr;
struct iovec iovec[5];
@ -78,26 +86,40 @@ static int stream_log(Stream *s, char *p, usec_t timestamp) {
return 0;
/*
* The format glibc uses is:
* The format glibc uses to talk to the syslog daemon is:
*
* <priority>time process[pid]: msg
*
* The format the kernel uses is:
*
* <priority>msg\n
*
* We extend the latter to include the process name and pid.
*/
snprintf(header_priority, sizeof(header_priority), "<%i>", s->priority);
snprintf(header_priority, sizeof(header_priority), "<%i>",
s->target == LOG_TARGET_SYSLOG ? s->priority : LOG_PRI(s->priority));
char_array_0(header_priority);
if (s->target == LOG_TARGET_SYSLOG) {
time_t t;
struct tm *tm;
t = (time_t) (timestamp / USEC_PER_SEC);
if (!(tm = localtime(&t)))
return -EINVAL;
if (strftime(header_time, sizeof(header_time), "%h %e %T ", tm) <= 0)
return -EINVAL;
}
snprintf(header_pid, sizeof(header_pid), "[%llu]: ", (unsigned long long) s->pid);
char_array_0(header_pid);
zero(iovec);
IOVEC_SET_STRING(iovec[0], header_priority);
if (s->target == LOG_TARGET_SYSLOG) {
IOVEC_SET_STRING(iovec[1], header_time);
IOVEC_SET_STRING(iovec[2], s->process);
IOVEC_SET_STRING(iovec[3], header_pid);
@ -107,9 +129,20 @@ static int stream_log(Stream *s, char *p, usec_t timestamp) {
msghdr.msg_iov = iovec;
msghdr.msg_iovlen = ELEMENTSOF(iovec);
if (sendmsg(s->server->log_fd, &msghdr, MSG_NOSIGNAL) < 0)
if (sendmsg(s->server->syslog_fd, &msghdr, MSG_NOSIGNAL) < 0)
return -errno;
} else if (s->target == LOG_TARGET_KMSG) {
IOVEC_SET_STRING(iovec[1], s->process);
IOVEC_SET_STRING(iovec[2], header_pid);
IOVEC_SET_STRING(iovec[3], p);
IOVEC_SET_STRING(iovec[4], "\n");
if (writev(s->server->kmsg_fd, iovec, ELEMENTSOF(iovec)) < 0)
return -errno;
} else
assert_not_reached("Unknown log target");
return 0;
}
@ -123,12 +156,34 @@ static int stream_line(Stream *s, char *p, usec_t timestamp) {
switch (s->state) {
case STREAM_PRIORITY:
if ((r = safe_atoi(p, &s->priority)) < 0)
return r;
case STREAM_LOG_TARGET:
if (streq(p, "syslog"))
s->target = LOG_TARGET_SYSLOG;
else if (streq(p, "kmsg")) {
if (s->priority < 0)
if (s->server->kmsg_fd >= 0 && s->uid == 0)
s->target = LOG_TARGET_KMSG;
else {
log_warning("/dev/kmsg logging not available.");
return -EPERM;
}
} else {
log_warning("Failed to parse log target line.");
return -EBADMSG;
}
s->state = STREAM_PRIORITY;
return 0;
case STREAM_PRIORITY:
if ((r = safe_atoi(p, &s->priority)) < 0) {
log_warning("Failed to parse log priority line: %s", strerror(errno));
return r;
}
if (s->priority < 0) {
log_warning("Log priority negative: %s", strerror(errno));
return -ERANGE;
}
s->state = STREAM_PROCESS;
return 0;
@ -271,6 +326,7 @@ static int stream_new(Server *s, int server_fd) {
}
stream->pid = ucred.pid;
stream->uid = ucred.uid;
stream->server = s;
LIST_PREPEND(Stream, stream, s->streams, stream);
@ -336,11 +392,14 @@ static void server_done(Server *s) {
for (i = 0; i < s->n_server_fd; i++)
assert_se(close_nointr(SERVER_FD_START+i) == 0);
if (s->log_fd >= 0)
assert_se(close_nointr(s->log_fd) == 0);
if (s->syslog_fd >= 0)
assert_se(close_nointr(s->syslog_fd) == 0);
if (s->epoll_fd >= 0)
assert_se(close_nointr(s->epoll_fd) == 0);
if (s->kmsg_fd >= 0)
assert_se(close_nointr(s->kmsg_fd) == 0);
}
static int server_init(Server *s, unsigned n_sockets) {
@ -357,7 +416,8 @@ static int server_init(Server *s, unsigned n_sockets) {
zero(*s);
s->n_server_fd = n_sockets;
s->log_fd = -1;
s->syslog_fd = -1;
s->kmsg_fd = -1;
if ((s->epoll_fd = epoll_create1(EPOLL_CLOEXEC)) < 0) {
r = -errno;
@ -378,7 +438,7 @@ static int server_init(Server *s, unsigned n_sockets) {
}
}
if ((s->log_fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0)) < 0) {
if ((s->syslog_fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0)) < 0) {
r = -errno;
log_error("Failed to create log fd: %s", strerror(errno));
goto fail;
@ -388,12 +448,16 @@ static int server_init(Server *s, unsigned n_sockets) {
sa.un.sun_family = AF_UNIX;
strncpy(sa.un.sun_path, "/dev/log", sizeof(sa.un.sun_path));
if (connect(s->log_fd, &sa.sa, sizeof(sa)) < 0) {
if (connect(s->syslog_fd, &sa.sa, sizeof(sa)) < 0) {
r = -errno;
log_error("Failed to connect log socket to /dev/log: %s", strerror(errno));
goto fail;
}
/* /dev/kmsg logging is strictly optional */
if ((s->kmsg_fd = open("/dev/kmsg", O_WRONLY|O_NOCTTY|O_CLOEXEC)) < 0)
log_debug("Failed to open /dev/kmsg for logging, disabling kernel log buffer support: %s", strerror(errno));
return 0;
fail:
@ -463,7 +527,6 @@ int main(int argc, char *argv[]) {
if (server_init(&server, n) < 0)
return 2;
for (;;) {
struct epoll_event event;
int n;